<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Different Criteria for Hiding "Children" of Collapsed Nodes</title>
<meta name="description" content="Custom policy for collapsing and expanding subtrees, different than TreeExpanderButton." />
<!-- Copyright 1998-2019 by Northwoods Software Corporation. -->
<meta charset="UTF-8">
<script src="../release/go.js"></script>
<script src="../assets/js/goSamples.js"></script>  <!-- this is only for the GoJS Samples framework -->
<script id="code">
function init() {
  if (window.goSamples) goSamples();  // init for these samples -- you don't need to call this
	var $ = go.GraphObject.make;

	myDiagram =
    $(go.Diagram, "myDiagramDiv",
      {
        initialContentAlignment: go.Spot.Center,
        padding: 10,
        layout: $(go.LayeredDigraphLayout,
                  { direction: 90, layeringOption: go.LayeredDigraphLayout.LayerLongestPathSource }),
        "undoManager.isEnabled": true
      });

	myDiagram.nodeTemplate =
		$(go.Node, go.Panel.Vertical,
      { portId: "", fromLinkable: true, toLinkable: true },
      new go.Binding("visible"),
			$(go.Panel, go.Panel.Auto,
				$(go.Shape,
          { fill: "white", minSize: new go.Size(30, 30), strokeWidth: 0 },
          { cursor: "pointer" },  // indicate that linking may start here
          new go.Binding("fill", "color")),
				$(go.TextBlock,
          { margin: 2 },
          { fromLinkable: false, toLinkable: false },  // don't start drawing a link from the text
          new go.Binding("text", "key"))),
			$("Button",  // a replacement for "TreeExpanderButton" that works for non-tree-structured graphs
        // assume initially not visible because there are no links coming out
        { visible: false },
        // bind the button visibility to whether it's not a leaf node
        new go.Binding("visible", "isTreeLeaf",
                       function(leaf) { return !leaf; })
            .ofObject(),
        $(go.Shape,
          {
            name: "ButtonIcon",
            figure: "MinusLine",
            desiredSize: new go.Size(6, 6)
          },
          new go.Binding("figure", "isCollapsed",  // data.isCollapsed remembers "collapsed" or "expanded"
                         function(collapsed) { return collapsed ? "PlusLine" : "MinusLine"; })),
        {
          click: function(e, obj) {
            e.diagram.startTransaction();
            var node = obj.part;
            if (node.data.isCollapsed) {
              expandFrom(node, node);
            } else {
              collapseFrom(node, node);
            }
            e.diagram.commitTransaction("toggled visibility of dependencies");
          }
        })
    );

	function collapseFrom(node, start) {
	  if (node.data.isCollapsed) return;
	  node.diagram.model.setDataProperty(node.data, "isCollapsed", true);
	  if (node !== start) node.diagram.model.setDataProperty(node.data, "visible", false);
	  node.findNodesOutOf().each(collapseFrom);
	}

	function expandFrom(node, start) {
	  if (!node.data.isCollapsed) return;
	  node.diagram.model.setDataProperty(node.data, "isCollapsed", false);
	  if (node !== start) node.diagram.model.setDataProperty(node.data, "visible", true);
	  node.findNodesOutOf().each(expandFrom);
	}

	myDiagram.linkTemplate =
		$(go.Link,
			{ relinkableFrom: true, relinkableTo: true, corner: 10 },
			$(go.Shape),
			$(go.Shape, { toArrow: "Standard" }));

	myDiagram.model = new go.GraphLinksModel([
    { key: "A", color: "lightgreen" },
    { key: "B1", color: "yellow" },
    { key: "B2", color: "yellow" },
    { key: "C", color: "lightblue" },
    { key: "D1", color: "orange" },
    { key: "D2", color: "orange" },
    { key: "E", color: "pink" },
    { key: "F", color: "lightgreen" },
    { key: "Z1", color: "lightgreen" },
	  { key: "Z2", color: "yellow" },
	  { key: "Z3", color: "orange" },
	  { key: "Z4", color: "pink" }
	], [
    { from: "A", to: "B1" },
    { from: "B1", to: "C" },
    { from: "A", to: "B2" },
    { from: "B2", to: "D2" },
    { from: "C", to: "D1" },
    { from: "C", to: "D2" },
    { from: "D1", to: "E" },
    { from: "D2", to: "E" },
    { from: "D2", to: "F" },
    { from: "Z1", to: "Z2" },
	  { from: "Z2", to: "Z3" },
	  { from: "Z3", to: "Z4" },
	  { from: "Z4", to: "Z1" }
	]);
}
</script>
</head>
<body onload="init()">
  <div id="sample">
    <div id="myDiagramDiv" style="border: solid 1px black; width:600px; height:700px"></div>
    <p>
      The "TreeExpanderButton", which changes the <a>Node.isTreeExpanded</a> property, really only works with tree structures.
      When you want to hide/show the "downstream" nodes from a given node, using the "TreeExpanderButton" might not do what you like,
      especially when there are cycles in the graph structure.
    </p>
    <p>
      Instead, this sample implements a "Button" with custom behavior to modify the visibility of each Node.
      If this behavior is still not quite right for your app, you can adapt the behavior implemented in the
      <pre>collapseFrom</pre> and <pre>expandFrom</pre> functions to use different criteria for when to stop recursion.
    </p>
  </div>
</body>
</html>
